Takakazu Morita

Hybrid Propulsion Technology Development in Japan for Economic Space Launch

The demand for the economic and dedicated space launchers for vast amount of lightweight, so-called nano-/microsatellites, is now growing rapidly. There is a strong rationale for the usage of the hybrid propulsion for economic space launch as suggested by the assessment conducted here. A typical concept of development of such an economic three-stage launcher, in which clustering unit hybrid rocket engines are employed, is described with a development scenario. Thanks to the benefits of hybrid rocket propulsion, assuring and safe, economic launcher dedicated to lightweight satellites can be developed with a reasonable amount of quality assurance and quality control actions being taken in all aspects of development such as raw material, production, transportation, storage, and operation. By applying a multi-objective optimization technique for such a launch system, examples of possible launch systems are obtained for a typical mission scenario for the launch of lightweight satellites. Furthermore, some important technologies that contribute strongly to economic space launch by hybrid propulsion are described. They are the behavior of fuel regression rate, the swirling-oxidizer-flow-type hybrid rocket, the liquid oxygen vaporization, the multi-section swirl injection, the low-temperature melting point thermoplastic fuel, the thrust and O/F simultaneous control by altering-intensity swirl-oxidizer-flow-type (A-SOFT) hybrid, the numerical simulations of the internal ballistics, and so on.

Development of laser sensing device both NH3 at 1.53µm and NO2 at 3.46µm at the same instant using laser absorption spectrometry

This paper reports on a trace gas monitor using a dual wavelength coherent light source. The laser spectrometer is based on difference frequency generation (DFG) techniques in a periodically poled lithium niobate (PPLN) crystal, naturally having two laser sources (i.e., signal and pump laser sources) in it. A newly proposed idea is to use residual signal DFB-LD power to tune to NH3 absorption lines around at 1.536 μm when the DFG output wavelengths are accessed at 3.46 μm. In the experiments, the signal DFB-LD was carefully tune the wavelength guided by HITRAN database in order to select appropriate mid-IR absorption lines of NO2, while the DFB-LD can detect simultaneously NH3 absorption lines. As results, both gaseous species were detected successfully with the same multi-pass optical cell in one DFG spectrometer scheme. Spectroscopic data both in near-IR and in mid-IR region, simulating flue gas condition are discussed in detail.

Measurement of transient absorption change of NO/sub 2/ at 3.46 /spl mu/m using difference frequency generation

Rapid NO/sub 2/ detection by mid-infrared coherent light source based on difference frequency generation that used a fiber laser as pumping source was demonstrated. High resolution spectroscopic measurements of NO/sub 2/ are reported.